Temperature management during the initial period after resuscitation from out-of-hospital cardiac arrest is an important factor in recovery. Induction of hypothermia improves outcomes in adults resuscitated from cardiac arrest. In addition, induction of hypothermia improves outcomes in neonates suffering from hypoxic ischemic encephalopathy. Temperature management may be of benefit in other conditions, such as spinal cord injury, stroke, meningitis and some subsets of traumatic brain injury. The general neuroprotective effects of mild therapeutic hypothermia mitigate both altitude and acceleration induced hypoxia, and more broadly, ischemia reperfusion injury. Moreover, temperature management in an operative setting may improve patient outcome and reduce adverse events. Nevertheless, therapeutic hypothermia is not readily available or used in all centers, let alone by emergency medical services (“EMS”) personnel.
Currently available methods to control body temperature include both non-invasive techniques, such as surface cooling, and invasive techniques, such as intravascular cooling. For example, methods currently used to induce hypothermia require skin contact with blankets or pads, or intravascular access with catheter devices. These methods involve some limitations inherent in their approach, and surveys suggest that the technical difficulties involved in some methods may contribute to the underuse of treatment. Specific challenges with intravascular devices include the need to invasively access central circulation via needle puncture, the requirement for sterility in the placement of catheters, and the need for physician time and expertise for placement. Specific challenges with skin contact devices include the need to cover large critical areas of the skin and inefficiency in heat exchange across the skin which results in longer times to achieve goal temperature.
Commercially available heat exchangers are designed for circulation of coolant for medical applications such as blankets, catheters, and extremity pads. For example, the Medi-Therm III Hyper/Hypothermia machine (Gaymar Industries, Inc.) supplies temperature controlled water to a blanket. Model MTA7912 Medi-Therm III Hyper/Hypothermia machine weighs 68.6 kg when empty and includes a reservoir that holds 9.5 liters of distilled water. Model MTA7900 Medi-Therm III Hyper/Hypothermia machine weighs 55 kg when empty and includes separate hot and cold water reservoirs. Model MTA7912 Medi-Therm III Hyper/Hypothermia machine is reported to be 94 cm high×48 cm deep×36 cm wide. Model MTA7900 Medi-Therm III Hyper/Hypothermia machine is reported to be 94 cm high×46 cm deep×36 cm wide. In a poor cooling environment (e.g., 90° F. ambient temperatures), the Medi-Therm III Hyper/Hypothermia machine has a cooling capacity of greater than 630 W.
Accordingly, there is a need for temperature management systems, methods of operating a temperature management system, and methods of managing patient temperature that are portable, convenient, and easily employed by physicians, EMS personnel, and other health care providers. There is a need for temperature management systems, methods of operating a temperature management system, and methods of managing patient temperature that can be employed in an out-of-hospital setting by, for example, EMS personnel.